Hereditary myelopathy of Afghan hounds, a myelinolytic disease.

A disease described previously as hereditary necrotizing myelopathy and myelomalacia was studied in four Afghan hounds. Light and electron microscopic investigation revealed sieve-like degeneration of spinal white matter. Despite extensive spongiform degeneration of myelin that progressed to micro- and macro-cavitation, substantial numbers of axons were preserved. This canine myelopathy was compared and contrasted with various toxic/metabolic conditions including subacute combined degeneration.